Vane type hydraulic actuator

Abstract

A vane type hydraulic actuator, wherein a chip seal 1, as a seal element between the case 43 and the rotor 44, can be pressed to contact tightly with the counter surface, without using a spring 47 as in the prior art, when a working oil is supplied either from the oil pressure chambers for timing retard or for timing advance. Simultaneously, the locking between the rotor 44 and the case 43 can be released. The hydrodynamic resistance at the gap between the tip of the seal element (chip seal) 1 and the counter surface of the seal element is made larger than that at the gap between the flank of the seal element 1 and the flank of the seal groove 2, which accomodates the seal element, so that the working oil of the hydraulic actuator flows between the flanks. The working oil at the bottom of the seal element urges the seal element to contact tightly with the counter surface. An oil channel 6 connects the bottom of the seal groove and a stopper pin holding hole 4, which holds a stopper pin 3 pressed by a spring 5. When a working oil is supplied from either of oil pressure chambers for timing retard or advance, the channel 6 opens to supply a working oil into the stopper pin holding hole 5 so as to displace the pin against the biasing force of the spring 5 to release the suppression of rotation.

Description

BACKGROUND OF THE INVENTION1. Field of the InventionThe present invention relates to a vane type hydraulic actuator for use, for example, in a valve timing adjusting apparatus, which controls the timing of opening and closing of an intake valve and / or exhaust valve of an engine, in response to the running condition of the engine.2. Description of the Prior ArtFIG. 23 is a cross sectional view of a vane type hydraulic actuator of the prior art, specifically, it is a vane type hydraulic actuator shown in Japanese Patent Application JP-A-314069 applied by the same applicant of this patent application. FIG. 24 is a detailed cross sectional view of the plunger portion of the actuator shown in FIG. 23, which is a main portion of the actuator. FIG. 25 is a cross sectional view of the plunger portion shown in FIG. 24, at a state when an oil pressure is applied.Reference numeral 19 denotes a cam shaft for an intake valve having a cam for the intake valve 19a. A timing pulley 21 is disposed a...

AI Technical Summary

Benefits of technology

Another object of the present invention is to provide a vane type hydraulic actuator, in which a force can be imposed to the chip seals to contact tightly with its counter surface, without using a supplemental biasing force generating means, for example, a spring, so that the productivity can be improved, and the production cost can be reduced.

Further another object of the present invention is to provide a vane type hydraulic actuator, in which the locking means of the rotation, for example, a plunger, can be released easily, without using a complex mechanism, such as a slide plate.

Problems solved by technology

The vane type hydraulic actuator of the prior art has a drawback, due to such a structure, that a biasing force generating means, for example, a spring 47 is necessary for pressing the chip seals 46, 68 for the tight contact between the vanes and the casing.

Thus the productivity is low and the production cost is high.

Namely the apparatus is complex, and productivity is low.

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